The U.S. Department of Energy's EnergySmart Schools provides school boards, administrators, and design staff with guidance to help them make informed decisions about energy and environmental issues important to school systems and communities. The design guidelines presented in this document outline high performance principles for the new or retrofit design of K-12 schools. The document presents recommended design elements in 10 sections, each representing a key interrelated component of high performance school design: (1) site design; (2) daylighting and windows; (3) energy-efficient building shell; (4) lighting and electrical systems; (5) mechanical and ventilation systems; (6) renewable energy systems; (7) water conservation; (8) recycling systems and waste management; (9) transporation; and (10) resource efficient building products. To effectively integrate energy-saving strategies, these options must be evaluated together from a whole-building perspective early in the design process. A high performance checklist for designers is located at the end of the document along with case studies. These guidelines contain recommendations generally appropriate for cool and dry climates, for which Denver, Colorado, served as a model city. Other guidelines have been developed for the other climate zones.